Fig. 1
A sequence of O8.5 through O9.7 spectra from the VFTS sample, to illustrate the new O9.2 type in terms of the He ii λλ4541, 4200/ He i λλ4387, 4144 and He ii λ4541/Si iii λ4552 criteria. λ4026 is a blend of He i and He ii, with the former predominating at late-O types. The ordinate scales in all spectroscopic figures are given in continuum units by the bar at lower right. These figures should be viewed online with at least 200% enlargement to fully appreciate their information content.
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